A known state of the art, U.S. Pat. No. 4,568,804, disclosure is shown in the FIG. 2. An insulating housing 1a and 1b, that contains a switching element 2 is located in an environment of high pressurized fluid. For example this can be a vacuum interrupter in a subsea application. The vacuum interrupter has to be protected against the high pressures, which can reach 300 bar or more. Therefore a pole part is needed, that withstands the pressure and keeps an atmospheric environment of 1-3 bar at the outer surface of the vacuum interrupter itself. The high pressurized fluid around is insulating fluid. This is in an enclosure on the seabed in order to prevent damage from contact with the seawater.